A signal intersection control system and method based on colored Petri net

Abstract

The present invention relates to the technical field of traffic signal control, and in particular to a signal intersection control system and method based on colored Petri nets. The present invention determines the position of a vehicle counter according to the definition of an intersection; tokens of different colors are used to represent different vehicle types; a modular model of an intersection path and a modular model of intersection path signal control are constructed according to the definition of an intersection; a Petri net model of an intersection is constructed by combining the modular models of the paths to establish a control model for a signal intersection. The model constructed by the present invention can well distinguish different types of vehicles, simulate various processes of vehicles passing through an intersection, and construct a complete intersection model by combining modular models. It has strong universality and is suitable for different types of intersections; the constructed model can flexibly connect to a signal control optimization model that meets the requirements, thereby improving traffic efficiency while ensuring vehicle safety.

Description

Technical Field

[0001] The present invention relates to the technical field of traffic signal control, and in particular to a signal intersection control system and method based on colored Petri nets. Background Art

[0002] At present, the number of cars continues to increase, the demand for travel increases, and road congestion and traffic conflicts become more serious. However, the road network in most cities has become mature, and the expansion space is limited. Solving the congestion problem through road construction is no longer a good way to adapt to the development rhythm of the city. It is extremely important to use the existing road network to arrange certain roads, especially signal control, to solve the above traffic problems.

[0003] The existing road network structure is complex, and it is difficult to fully grasp all types of road networks, and it is impossible to establish signal control algorithms for all types one by one. Therefore, a traffic model that can be applied to most types of intersections is needed, and the model is required to be able to flexibly adjust the signal light timing scheme. The present invention uses colored Petri nets to establish a basic framework to establish a model to solve the signal control problem of signal intersections. Summary of the invention

[0004] In order to solve the technical problem that it is difficult to establish signal control for all types in the prior art, the purpose of the present invention is to provide a signal intersection control system and method based on colored Petri nets, and the technical solution adopted is as follows:

[0005] In a first aspect, an embodiment of the present invention provides a signalized intersection control system based on a colored Petri net, wherein the signalized intersection control system includes a signalized intersection model based on a colored Petri net, wherein the model includes the following modules:

[0006] Initial definition module, used to define intersections;

[0007] A vehicle representation module is used to determine the position of a vehicle counter according to the definition of the intersection; different colored tokens are used to represent different vehicle types;

[0008] A modular model building module, used to build a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection;

[0009] The control model construction module is used to connect the modular model of the intersection with directed arcs according to the direction of vehicle travel, and build a Petri net model of the intersection; based on the Petri net model of the intersection, a signal control model that can eliminate conflicts is built according to path conflicts; based on the signal control model of the intersection, relevant signal control optimization models are connected according to actual needs.

[0010] Furthermore, a modular model of intersection path signal control is constructed, including:

[0011] For each path of the intersection, a modular model of signal control is established The modular model uses two libraries Hekushu Describe the green light state and red light state respectively, There is a token inside corresponding to the path The signal is green, and There is a token inside corresponding to the path The signal is red;

[0012] Define two transitions and Indicates the switching of the signal light;

[0013] Define a directed arc: , , and .

[0014] Furthermore, according to the direction of vehicle travel, the modular model of the intersection is connected with directed arcs to construct a Petri net model of the intersection, including:

[0015] For each path at the intersection, according to the driving direction of the vehicle on the current path, all modular models belonging to the path are connected from top to bottom through one-way arcs. , , ;

[0016] For each path model Modular model controlled by bidirectional arcs and their signals connect;

[0017] The signal control optimization model is connected by directed arcs on the Petri net model of the intersection.

[0018] Furthermore, the properties that the signal control model must satisfy are:

[0019] 1. Each path A library that indicates the status of a traffic light and In , the total number of tokens is always 1;

[0020] 2. Each path Green Light Library When there is a token, all Conflicting Paths Green Light Library Neither have tokens.

[0021] 3. When the path When the traffic light changes from red to green, all paths that conflict with this path The corresponding library indicating the red light state has a token; the path When the signal light turns green, these tokens will be locked in the above library indicating the red light state until all conflicting paths (including ) turns red.

[0022] Furthermore, the intersection definition includes:

[0023] Differentiate the entrance roads:

[0024] First, they are distinguished by path. When lanes at different entrances have the same path, they are classified as the same entrance road.

[0025] Then, according to the lane distinction, when different paths share the same entrance road, the entrance roads shared by different paths belong to the same entrance road;

[0026] According to the intersection layout, it is divided into entrance roads into the intersection , the non-changeable lane immediately following the entrance road , the path through the intersection followed by the immutable lane , respectively , and describe Enter The front part, entering But didn't enter Parts and entry part.

[0027] Further, the determining of the vehicle counter position according to the definition of the intersection includes:

[0028] A first vehicle counter is placed on the entrance road of the intersection, wherein the distance between the vehicle counter and the intersection is not less than the distance that a vehicle passes within one green light duration when traveling at a free speed, and not greater than the distance that a vehicle passes within two green light durations;

[0029] A second vehicle counter is provided at the entrance of each non-changeable lane close to the intersection;

[0030] A third vehicle counter is respectively set at the exit of each path entering the intersection.

[0031] A fourth vehicle counter is respectively set at the exit of each path leaving the intersection.

[0032] Furthermore, the tokens of different colors are used to represent different vehicle models, including:

[0033] The upstream counter of each entry road corresponds to a transition , the transition has a dedicated library Connected by a bidirectional directed arc; each place There are the same number of tokens as the number of car models, and the color of each token represents a car model.

[0034] Furthermore, the modular model of the intersection path includes:

[0035] Modular model for each path , , Each contains a and changes and a directed arc connecting the two The structure composed of ;

[0036] Medium Change Both are connected by a bidirectional directed arc ;

[0037] Central Library Connect to a single transition superior;

[0038] Furthermore, the modular model of the intersection path also includes:

[0039] Each first, second, and third counter in each path consists of a directed arc Connection Library Changes ,in The modular models corresponding to the path , , ;

[0040] Each fourth counter in each path is connected to a separate transition .

[0041] In a second aspect, a signalized intersection control method based on a colored Petri net is provided, the method comprising the following steps:

[0042] S1, define the intersection;

[0043] S2, determining the position of the vehicle counter according to the definition of the intersection; using tokens of different colors to represent different vehicle models;

[0044] S3, constructing a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection;

[0045] S4, according to the direction of vehicle travel, use directed arcs to connect the modular model of the intersection path to build a Petri net model of the intersection; based on the Petri net model of the intersection, build a signal control model that can eliminate conflicts according to path conflicts; based on the signal control model of the intersection, connect related signal control optimization models according to actual needs.

[0046] The embodiments of the present invention have at least the following beneficial effects:

[0047] The present invention refines the entrance road of the intersection, and can show the whole process of the traffic flow through the intersection in detail, while making the traffic model have the advantage of modularization; by using colored Petri nets to establish a basic framework, different vehicle models can be well distinguished, so as to provide optimization solutions for different vehicle models; a colored Petri net model of relevant roads, vehicles, signal lights and conflicting paths is established, which can more completely show the details of traffic demand; modular modeling of the intersection is carried out, and a complete intersection model is constructed by combining modular models, which has strong universality and is suitable for different types of intersections; the two properties required by the present invention ensure that the conflicting paths will not be in the green light state at the same time, thereby affecting the normal passage of vehicles through the intersection, and ensuring driving safety; for the road intersection signal model that meets the requirements of the present invention, except for the restriction on the signal combination of the conflicting paths, there are no other restrictions, and the timing plan has the largest adjustable space, thereby improving the traffic capacity of the intersection. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 A schematic diagram of a module of a signalized intersection model based on a colored Petri net provided by an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of the position of a vehicle counter provided by an embodiment of the present invention;

[0051] Figure 3 A path provided by an embodiment of the present invention Schematic diagram of the Petri net model of the intersection;

[0052] Figure 4 A connection example diagram of a signal control optimization model provided by an embodiment of the present invention;

[0053] Figure 5 A flow chart of a process of a vehicle passing through an intersection on a path provided by an embodiment of the present invention;

[0054] Figure 6 A schematic diagram of a common "cross" intersection provided by an embodiment of the present invention;

[0055] Figure 7 Corresponding to an embodiment of the present invention Figure 6 The signal control model for the intersection shown does not eliminate path conflicts;

[0056] Figure 8 Corresponding to an embodiment of the present invention Figure 6 The signal control model after all path conflicts are eliminated at the intersection shown;

[0057] Fig. 9 A schematic diagram of a common "T"-shaped intersection provided by an embodiment of the present invention;

[0058] Fig.10 Corresponding to an embodiment of the present invention Fig. 9 The signal control model when the intersection shown does not eliminate the path conflict;

[0059] Fig.11 Corresponding to an embodiment of the present invention Fig. 9 The signal control model after all path conflicts are eliminated at the intersection shown;

[0060] Fig.12 A flowchart of a signalized intersection control method based on colored Petri nets is provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following, in combination with the accompanying drawings and preferred embodiments, a signal intersection control system and method based on colored Petri nets proposed by the present invention, its specific implementation method, structure, characteristics and effects are described in detail as follows.

[0062] In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0063] Among them, in the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a way to describe the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" refers to two or more than two.

[0064] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0065] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0066] The embodiments of the present invention are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present invention are also applicable to similar technical problems.

[0067] The specific scheme of a signalized intersection control system and method based on colored Petri nets provided by the present invention is described in detail below with reference to the accompanying drawings.

[0068] Embodiment 1:

[0069] An embodiment of the present invention provides a signalized intersection control system based on a colored Petri net. The signalized intersection control system includes a signalized intersection model based on a colored Petri net. Figure 1 , which shows a module schematic diagram of a signal intersection model based on a colored Petri net, the model includes the following modules:

[0070] The initial definition module 10 is used to define the intersection.

[0071] For intersections, they are defined according to the usual road marking rules and intersection structure, specifically:

[0072] The entrance roads are first distinguished according to the paths. When lanes at different entrances have the same paths, the lanes at different entrances are classified as the same entrance road. Then, they are distinguished according to the lanes. When different paths share an entrance road, the entrance roads shared by different paths are classified as the same entrance road.

[0073] According to the usual intersection road layout, it is divided into the entrance road into the intersection and its collection , Each immutable lane d entering the intersection at the lower end and its set , followed by the immutable lane The path through the intersection and its collection , where vehicles with different turns are already in the lanes of the corresponding paths.

[0074] entrance road , and , respectively , and express Enter The front part, entering But didn't enter Parts and entry part.

[0075] The vehicle representation module 20 is used to determine the position of the vehicle counter according to the definition of the intersection; different colored tokens are used to represent different vehicle models.

[0076] The vehicle counter is mainly used to detect whether the vehicle has reached the next part of the route and also has the function of distinguishing vehicle types. Figure 2 , Figure 2 This is a schematic diagram of the vehicle counter location. Figure 2 Counter1, Counter2 and Counter3 represent the set vehicle counters, Counter1 is recorded as the first vehicle counter, Counter2 is recorded as the second vehicle counter, Counter3 is recorded as the third vehicle counter, and Counter4 is recorded as the fourth vehicle counter.

[0077] The entrance road to the intersection has a large distance to the first vehicle counter Counter1, the distance between the vehicle counter and the intersection is not less than the distance that the vehicle passes within one green light duration when driving at free speed, and not greater than the distance that the vehicle passes within two green light durations;

[0078] A second vehicle counter Counter2 is set at the entrance of each immutable lane close to the intersection;

[0079] A third vehicle counter Counter3 is set at each exit of the intersection;

[0080] A fourth vehicle counter Counter4 is respectively set at the exit of each path from the intersection.

[0081] Determine the type of vehicle based on its length, appearance and other features, and classify it into the vehicle category to which it belongs;

[0082] Each entrance road has a dedicated storage facility. , which contains the same number of tokens as the number of car models, and the color of each token represents a car model.

[0083] The modular model building module 30 is used to build a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection.

[0084] First, a modular model of each path is constructed. Each first, second, and third counter in each path contains a directed arc Connection Library Changes ,in The modular models corresponding to the path , , ; Each fourth counter in each path is connected to a separate transition .

[0085] For each path of the intersection, a modular model of signal control is established The modular model uses two libraries Hekushu Describe the green light state and red light state respectively, There is a token inside corresponding to the path The signal is green, and There is a token inside corresponding to the path The signal is red;

[0086] Define two transitions and Indicates the switching of the signal light;

[0087] Define a directed arc: , , and .

[0088] The control model building module 40 is used to link the modular model of the intersection path with directed arcs according to the vehicle driving direction to build a Petri net model of the intersection; based on the Petri net model of the intersection, a signal control model that can eliminate conflicts is built according to path conflicts.

[0089] For each path at the intersection, according to the driving direction of the vehicle on the current path, all modular models belonging to the path are connected from top to bottom through one-way arcs. , , ;

[0090] For each path model Modular model controlled by bidirectional arcs and their signals connect;

[0091] The signal control optimization model is connected by directed arcs on the Petri net model of the intersection.

[0092] For each , the corresponding library There can be at most one token in a column, and the color of the token is The same as the path that indicates controlled entry; in this way, triggering A necessary condition is There is a token in The trigger corresponds to the vehicle entering the path .

[0093] After connecting all modular models on the same path, including the modular models of all intersection paths and the modular models of signal control on the path. Figure 3 , Figure 3 For path Petri net model of the intersection.

[0094] For the signal control optimization model, it can be flexibly connected to the appropriate modular model through directed arcs, including but not limited to:

[0095] The signal control procedure that opens the priority passage for the vehicle category with high right of way, that is, the library of each entrance road Connect a Transition Corresponding to the signal-controlled right-of-way procedure, only It can only be triggered when a token of a specific color appears in the game.

[0096] Trigger the delayed green light procedure for certain types of vehicles, that is, add corresponding transitions for specific types of vehicles that need to delay turning on the green light , for each path's library Add a transition that can be triggered by any color token. The triggering of this transition will add a token to the library corresponding to the color of the token, so that the system can make a decision on delaying the opening of the green light signal for this type of vehicle.

[0097] The optimal green light duration is calculated based on the vehicle type and number recorded by the counter, that is, based on the number of vehicles added to the library per unit time. and The number and color of tokens in the are used to estimate the traffic flow and calculate the optimal green light duration.

[0098] See also Figure 4 , Figure 4 Example diagram of the connections for optimizing the model for signal control.

[0099] It should be noted that the signal control optimization model can be arbitrary, and in the Petri net model of the intersection, the driving safety of vehicles can be guaranteed.

[0100] The Petri net model of the intersection through this path can simulate the driving process of vehicles through the intersection:

[0101] When a vehicle enters each path, the number and type of tokens in the place Arrival(w) remain unchanged. The counters arranged on the path will trigger the corresponding transition of the counter in sequence when the vehicle passes by according to its driving direction. The transition will transfer the token colored by the vehicle model in the corresponding place in the direction of the directed arc.

[0102] See also Figure 5 , Figure 5 This is a flow chart of the driving process of the path vehicle through the intersection:

[0103] For each , each time the counter at the most upstream counts a car of a certain model, Is triggered once, Add a token with the color of the car model, and The number of tokens in and their types remain unchanged. Lanes with no lane change at the bottom The counter at the entrance counts each time a car of a certain model enters. , Is triggered once, The number of tokens with the color of the model decreases by one, and The number of tokens with the color of the vehicle type increases by one; whenever a vehicle of a certain type moves from a non-changeable lane Enter the path , Decrease the model's token by one, and Add a token for this vehicle model; when the corresponding traffic light is green, There is a token in leave, is triggered, causing Subtract a token with the model as the color.

[0104] For the listed external signal control optimization parts, specifically:

[0105] Let a represent the type of vehicle with the highest right of way, Connect a Transition Represents an external priority signal control program. This transition can only be triggered by a token of a specific color. Considering that vehicles that are already on the entrance road cannot change lanes in general, once a type A vehicle appears, the vehicle in front should be released as soon as possible to allow this type of vehicle to pass through the intersection as quickly as possible.

[0106] Defining places Only colors can be placed Token, indicating that there is a corresponding The vehicle with the color token is passing through the intersection. The time required for this type of vehicle to safely pass through the intersection is ; In addition, there is a special transition With library connected to help the system make decisions to delay turning on the green light.

[0107] Specifically, if the path There is a large trailer of type i on the intersection, and the vehicle enters the intersection The traffic light of The signal light will be less than turns green at the time of When the traffic light turns red, The time it takes for traffic lights on the path to turn green will be delayed appropriately.

[0108] Add to the library according to the unit time and Kusuo The number of tokens and their colors in the ,estimate the queued vehicles in the next cycle and the vehicles entering the intersection from each path, and then calculate the optimal green light duration.

[0109] See also Figure 6 , Figure 6 It is a schematic diagram of a common "cross" intersection; N is the north direction, w3l is the left turn path of the west entrance; w3u is the U-turn path of the west entrance; w2s and w1s are the straight paths of the west entrance; w1r is the right turn path of the west entrance; n3l is the left turn path of the north entrance; n1s and n2s are the straight paths of the north entrance; n1r is the right turn path of the north entrance; e3l is the left turn path of the east entrance; e2s is the straight path of the east entrance; e1r is the right turn path of the east entrance; s3l is the left turn path of the south entrance; s2s and s1s are the straight paths of the south entrance; s1r is the right turn path of the south entrance.

[0110] See also Figure 7 , Figure 7 For the corresponding Figure 6 The intersection shown does not eliminate the signal control model of the path conflict.

[0111] Construct a modular model of the intersection path of the path, specifically:

[0112] like Figure 6 The "cross" intersection shown has four entrance roads: north, south, east, and west. Indicates that and Name the intersection places and transitions for the rules, where Corresponding library , Coping with changes , Respectively In addition, in order to distinguish different paths and the corresponding traffic lights, the entrance road orientation is used (North, South, East, West) and traffic flow redirection (U-turn, left turn, go straight, right turn) for marking.

[0113] Construct a modular model of intersection path signal control for this path.

[0114] A Petri net model of the intersection of the path is constructed through a modular model of the intersection path signal control and a modular model of the intersection path.

[0115] It should be noted that the common parts of multiple paths correspond to the same modular model; multiple paths that always respond to the same signal light share the same modular model controlled by the signal.

[0116] After constructing the Petri net model of the intersection, a signal control model that can eliminate conflicts is constructed based on the Petri net model of the intersection and according to the path conflicts. Specifically:

[0117] Add each with Conflicting Paths The restriction that the green lights cannot be on at the same time, that is, the definition of directed arcs and ; Given a path , There is a token inside corresponding to the path The signal is green, and There is a token inside corresponding to the path The signal is red.

[0118] As a preferred embodiment of the present invention, the signal control framework of the signal control model is:

[0119] Step 1: Set the initial state of the signal control model.

[0120] There is no uniform regulation for the setting of the initial state, but it must meet the following requirements: and One of them has a color tokens in one and no tokens in the other, and for each path in the green state, each conflicting path The corresponding library There is a token inside;

[0121] It should be noted that a simple option to meet the above requirements is to first set all signals to red, but immediately turn on some green lights under the constraints of the signal control framework.

[0122] Step 2: Given the properties that the signal control model must satisfy during the entire control process under the premise of meeting the initial state requirements.

[0123] 1. Each path A library that indicates the status of a traffic light and In , the total number of tokens is always 1;

[0124] 2. Each path Green Light Library When there is a token, all Conflicting Paths Green Light Library Neither have tokens.

[0125] 3. When the path When the traffic light changes from red to green, all paths that conflict with this path The corresponding library indicating the red light state has a token; the path When the signal light turns green, these tokens will be locked in the above library indicating the red light state until all conflicting paths (including ) turns red.

[0126] In some embodiments, a "cross" intersection is used as an example for explanation. Figure 6 As shown in the figure, assuming that each lane responds to the signal light independently, the signal control model of the signalized intersection based on the colored Petri net is as follows: Figure 7 See Figure 8 , Figure 8 For the corresponding Figure 6 The signal control model of the intersection shown is after all path conflicts are eliminated.

[0127] Figure 6 At the intersection shown in , the paths that conflict with the straight paths n1s and n2s of the north entrance are the left turn path s3l of the south entrance, the straight path e2s of the east entrance, and the straight paths w1s, w2s and left turn path w3l of the west entrance.

[0128] Specifically, taking the green light for going straight at the north entrance of the intersection as an example, in order to avoid conflicts, the traffic light of the conflicting path of the north entrance straight path cannot be green:

[0129] The straight path of the north entrance is in the green light state, and the corresponding places G(n1) and G(n2) have tokens, while the places R(n1) and R(n2) representing the red light state have no tokens; the conflicting paths of this path (the left turn path s3l of the south entrance, the straight path e2s of the east entrance, and the straight paths w1s, w2s and left turn path w3l of the west entrance) have tokens in the places R(s3), R(e2), R(w1), R(w2), and R(w3) representing the red light state, and have no tokens in the places G(s3), G(e2), G(w1), G(w2), and G(w3) representing the green light state. Select one of the conflicting paths, s3l, for detailed explanation: At this time, there are no tokens in the libraries R(n1) and R(n2). Although there is a token in the red light library R(s3) corresponding to the conflicting path s3l between n1s and n2s, the token is locked and cannot trigger the transition TG[s3], thus ensuring that the traffic light of s3l cannot turn green. When both n1s and n2s turn red, the tokens in the libraries G(n1) and G(n2) move to the red light library R(n1) and R(n2), and the transition TG[s3] of s3l is triggered. The token moves from R(s3) to G(s3), and s3l is in the green light state.

[0130] Figure 8 For Figure 6 The control model of the signalized intersection at the "cross" intersection shown is the result after all path conflicts are eliminated based on the colored Petri net.

[0131] Figure 8All right-turn paths have no conflicting paths with U-turns; the paths that conflict with the straight path of the north entrance are the left-turn path of the south entrance, the straight path of the east entrance, and the straight path and left-turn path of the west entrance; the paths that conflict with the left-turn path of the north entrance are the straight path of the south entrance, the straight path and left-turn path of the east entrance, and the left-turn path of the west entrance; the paths that conflict with the south entrance path are the left-turn path of the north entrance, the straight path and left-turn path of the east entrance, and the straight path of the west entrance; the paths that conflict with the south entrance path are the straight path of the north entrance, the left-turn path of the east entrance, and the straight path and Left-turn path; the paths that conflict with the straight path of the east entrance are the straight path and left-turn path of the north entrance, the straight path of the south entrance, and the left-turn path of the west entrance; the paths that conflict with the left-turn path of the east entrance are the left-turn path of the north entrance, the straight path and left-turn path of the south entrance, and the straight path of the west entrance; the paths that conflict with the straight path of the west entrance are the straight path of the north entrance, the straight path and left-turn path of the south entrance, and the left-turn path of the east entrance; the paths that conflict with the left-turn path of the west entrance are the straight path and left-turn path of the north entrance, the left-turn path of the south entrance, and the straight path of the east entrance.

[0132] In another embodiment of the present invention, see Fig. 9 , Fig. 9 is a schematic diagram of a common "T"-shaped intersection; among them, w3l is the left-turn path of the west entrance; w2s and w1s are the straight paths of the west entrance; n3l and n2l are the left-turn paths of the north entrance; n1r is the right-turn path of the north entrance; e3u is the U-turn path of the east entrance; e2s is the straight path of the east entrance; and e1r is the right-turn path of the east entrance. Assuming that the two left-turn paths of the north entrance are controlled by the same signal light, and the straight path of the west entrance is controlled by the same signal light, Fig.10 For the corresponding Fig. 9 The signal control model when the intersection shown does not eliminate the path conflict;

[0133] Fig. 9 The conflicting paths for the intersection shown in are:

[0134] All right-turn paths and U-turn paths have no conflicting paths. The left turn at the north entrance and the straight-through path at the west entrance are both two-lane paths. It is assumed that there is a conflict between the two. The paths that conflict with the left-turn path at the north entrance are the straight-through path at the east entrance, the straight-through path at the west entrance, and the left-turn path at the left entrance; the paths that conflict with the straight-through path at the east entrance are the left-turn path at the north entrance and the left-turn path at the west entrance; the paths that conflict with the straight-through path at the west entrance are the left-turn path at the north entrance; and the paths that conflict with the left-turn path at the west entrance are the left-turn path at the north entrance and the straight-through path at the east entrance.

[0135] See also Fig.11 , Fig.11 For the corresponding Fig. 9The signal control model of the intersection shown is after all path conflicts are eliminated.

[0136] Embodiment 2:

[0137] See also Fig.12 , Fig.12 A flowchart of a signalized intersection control method based on a colored Petri net is provided for the second embodiment. The method comprises:

[0138] S1, define the intersection;

[0139] S2, determining the position of the vehicle counter according to the definition of the intersection; using tokens of different colors to represent different vehicle models;

[0140] S3, constructing a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection;

[0141] S4, according to the direction of vehicle travel, use directed arcs to connect the modular model of the intersection path to build a Petri net model of the intersection; based on the Petri net model of the intersection, build a signal control model that can eliminate conflicts according to path conflicts; based on the signal control model of the intersection, connect related signal control optimization models according to actual needs.

[0142] Regarding the connection of related signal control optimization models according to actual needs, for example, a simple fixed-time control model can be connected to realize the connection of the library and transition that realizes the timing function on this model, so that the tokens in the red light library and the green light library in this model can be transferred according to a certain time rule. For example, a vehicle sensing control model can be connected, and the triggering of the transition corresponding to the vehicle counter in this model can be used as an input condition of the vehicle sensing control model, thereby dynamically adjusting the transfer of tokens in the traffic light library.

[0143] It should also be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0144] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0145] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0146] The above contents are only specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A signalized intersection control system based on colored Petri nets, characterized in that: The signalized intersection control system includes a signalized intersection model based on a colored Petri net, which includes the following modules: Initial definition module, used to define intersections; A vehicle representation module is used to determine the position of a vehicle counter according to the definition of the intersection; different colored tokens are used to represent different vehicle types; A modular model building module, used to build a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection; The control model building module is used to connect the modular model of the intersection with directed arcs according to the direction of vehicle travel, and build a Petri net model of the intersection; based on the Petri net model of the intersection, a signal control model that can eliminate conflicts is built according to path conflicts; based on the signal control model of the intersection, related signal control optimization models are connected according to actual needs; The signal control model always satisfies the following properties:

1. Each path A library that indicates the status of a traffic light and In , the total number of tokens is always 1; 2. Each path Green Light Library When there is a token, all Conflicting Paths Green Light Library Neither have tokens; 3. When the path When the traffic light changes from red to green, all paths that conflict with this path The corresponding library indicating the red light state has a token; the path After the traffic light turns green, these tokens will be locked in the above-mentioned library indicating the red light state until the traffic lights of all conflicting paths turn red; Among them, the signal control program for opening priority passage for vehicle categories with high priority rights, that is, the library of each entrance road Connect a Transition Corresponding to the signal-controlled right-of-way procedure, only It can only be triggered when a token of a specific color appears in the game. Among them, the delayed green light program is triggered for certain types of vehicles, that is, corresponding changes are added for specific types of vehicles that need to delay turning on the green light , for each path's library Add a transition that can be triggered by any color token. The triggering of this transition will add a token to the library corresponding to the token color, so that the system can make a decision on the delayed opening of the green light signal for this type of vehicle. The optimal green light duration is calculated based on the vehicle type and number recorded by the counter, that is, based on the number of vehicles added to the library per unit time. and The number and color of tokens in the estimation of traffic flow to calculate the optimal green light duration; The intersection is defined as follows: Differentiate the entrance roads: First, they are distinguished by path. When lanes at different entrances have the same path, they are classified as the same entrance road. Then, according to the lane distinction, when different paths share the same entrance road, the entrance roads shared by different paths belong to the same entrance road; According to the intersection layout, it is divided into entrance roads into the intersection , the non-changeable lane immediately following the entrance road , the path through the intersection followed by the immutable lane , respectively , and describe Enter The front part, entering But didn't enter Parts and entry part.

2. The signalized intersection control system based on colored Petri net according to claim 1 is characterized in that: Construct a modular model for intersection path signal control, including: For each path of the intersection, a modular model of signal control is established The modular model uses two libraries Hekushu Describe the green light state and red light state respectively, There is a token inside corresponding to the path The signal is green, and There is a token inside corresponding to the path The signal is red; Define two transitions and Indicates the switching of the signal light; Define a directed arc: , , and .

3. The signalized intersection control system based on colored Petri net according to claim 1 is characterized in that: According to the direction of vehicle travel, the modular model of the intersection is connected with directed arcs to construct the Petri net model of the intersection, including: For each path at the intersection, according to the driving direction of the vehicle on the current path, all modular models belonging to the path are connected from top to bottom through one-way arcs. , , ; For each path model Modular model controlled by bidirectional arcs and their signals connect; The signal control optimization model is connected by directed arcs on the Petri net model of the intersection.

4. The signalized intersection control system based on colored Petri net according to claim 1, characterized in that: Determining the position of the vehicle counter according to the definition of the intersection includes: A first vehicle counter is placed on the entrance road of the intersection, wherein the distance between the vehicle counter and the intersection is not less than the distance that a vehicle passes within one green light duration when traveling at a free speed, and not greater than the distance that a vehicle passes within two green light durations; A second vehicle counter is provided at the entrance of each non-changeable lane close to the intersection; A third vehicle counter is provided at each exit of the intersection; A fourth vehicle counter is respectively set at the exit of each path leaving the intersection.

5. The signalized intersection control system based on colored Petri net according to claim 1, characterized in that: The tokens of different colors are used to represent different models, including: Determine the type of vehicle based on its length, appearance and other features, and classify it into the vehicle category to which it belongs; Each entrance road has a dedicated storage facility. , which contains the same number of tokens as the number of car models, and the color of each token represents a car model.

6. The signalized intersection control system based on colored Petri net according to claim 1, characterized in that: The modular model of the intersection path includes: Modular model for each path , , Each contains a and changes and a directed arc connecting the two The structure composed of ; Medium Change Both are connected by a bidirectional directed arc ; Central Library Connect to a single transition superior.

7. The signalized intersection control system based on colored Petri net according to claim 1, characterized in that: The modular model of the intersection path also includes: Each first, second, and third counter in each path consists of a directed arc Connection Library Changes ,in The modular models corresponding to the path , , ; Each fourth counter in each path is connected to a separate transition .

8. A signalized intersection control method based on colored Petri nets, characterized in that: The method comprises the following steps: S1, define the intersection; S2, determining the position of the vehicle counter according to the definition of the intersection; using tokens of different colors to represent different vehicle models; S3, constructing a modular model of the intersection path and a modular model of the intersection path signal control according to the definition of the intersection; S4, according to the direction of vehicle travel, connect the modular model of the intersection with directed arcs to build a Petri net model of the intersection; based on the Petri net model of the intersection, build a signal control model that can eliminate conflicts according to path conflicts; based on the signal control model of the intersection, connect related signal control optimization models according to actual needs; The signal control model always satisfies the following properties:

1. Each path A library that indicates the status of a traffic light and In , the total number of tokens is always 1; 2. Each path Green Light Library When there is a token, all Conflicting Paths Green Light Library Neither have tokens; 3. When the path When the traffic light changes from red to green, all paths that conflict with this path The corresponding library indicating the red light state has a token; the path After the traffic light turns green, these tokens will be locked in the above-mentioned library indicating the red light state until the traffic lights of all conflicting paths turn red; Among them, the signal control program for opening priority passage for vehicle categories with high priority rights, that is, the library of each entrance road Connect a Transition Corresponding to the signal-controlled right-of-way procedure, only It can only be triggered when a token of a specific color appears in the game. Among them, the delayed green light program is triggered for certain types of vehicles, that is, corresponding changes are added for specific types of vehicles that need to delay turning on the green light , for each path's library Add a transition that can be triggered by any color token. The triggering of this transition will add a token to the library corresponding to the token color, so that the system can make a decision on the delayed opening of the green light signal for this type of vehicle. The optimal green light duration is calculated based on the vehicle type and number recorded by the counter, that is, based on the number of vehicles added to the library per unit time. and The number and color of tokens in the estimation of traffic flow to calculate the optimal green light duration; The intersection is defined as follows: Differentiate the entrance roads: First, they are distinguished by path. When lanes at different entrances have the same path, they are classified as the same entrance road. Then, according to the lane distinction, when different paths share the same entrance road, the entrance roads shared by different paths belong to the same entrance road; According to the intersection layout, it is divided into entrance roads into the intersection , the non-changeable lane immediately following the entrance road , the path through the intersection followed by the immutable lane , respectively , and describe Enter The front part, entering But didn't enter Parts and entry part.

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